"The Last Days of Disco Stick" is the 10th episode of the third season of the American teen drama television series Gossip Girl, and the 53rd episode overall. Written by Leila Gerstein and directed by Tony Wharmby, it originally aired on The CW on November 16, 2009. The episode features a cameo appearance and special performance by Lady Gaga, and marks the last appearance of Hilary Duff on the series.